HCIL-2006-19

Networks have remained a challenge for information visualization designers because of the complex issues of node and link layout coupled with the rich set of tasks that users present. This paper offers a strategy based on two principles: (1) layouts are based on user-defined semantic substrates, which are non-overlapping regions in which node placement is based on node attributes, (2) users interactively control link visibility to limit clutter and thus ensure comprehensibility of source and destination. To further limit display clutter, users can adjust sliders to control which nodes within a region have their edges visible. Scalability is further facilitated by user control of which nodes are visible. We illustrate our semantic substrates approach as implemented in NVSS 1.0 with legal precedents for up to 1122 cases in three regions with 7645 precedents.